词法解析程序
来源：岁月联盟
时间：2012-06-25
/**
* 2012年6月25日 中午
*
* 山东科技大学信息学院 版权所有
*
* 联系邮箱：www.2cto.com
*
* Copyright @ 2012, sdust, All Rights Reserved
*
* @author 王昌帅
*
*/
#include <stdio.h>
#include<stdlib.h>
#include<string.h>
#include<conio.h>
#define MAX_LENGTH 10
#define NUM_RESERVED_WORD 32
#define NUM_OPERATOR 5
#define NUM_SEPARATOR 16
//函数声明
void input(char*);
int judge(char*);
void parse2Array(char*);
int isChar(char c);
int isOperator(char c);
int isSeparator(char c);
int isNum(char c);
//输出信息
void output();
//判断是否是基本保留字(参数：字符串)
int isReservedWord_str(char* str);
//判断是否是操作符(参数：字符串)
int isOperator_str(char* str);
//判断是否是操作符(参数：字符串)
int isSeparator_str(char* str);
//判断是否是数字串(参数：字符串)
int isNum_str(char* str);
//判断是否是标识符(参数：字符串)
int isIndentifier_str(char* str);
//定义标识符
char sign_reserved_word[][MAX_LENGTH] = {"auto","double","int","struct","break","else","long","switch","case","enum","register","typedef","char","extern","return","union","const","float","short","unsigned","continue","for","signed","void","default","goto","sizeof","volatile","do","if","while","static"};
char sign_operator[][MAX_LENGTH] = {"+","-","*","/","%"};
char sign_separator[][MAX_LENGTH] = {"/n"," ","/"","/t",",",";",":","'","<",">","(",")","{","}","[","]"};
//单词总数（包括运算符、分隔符等）
int wordNum = 0;
//解析好的单词
char array[200][20];
//主函数
int main()
{
char str[500];
while(1)
{
input(str);
parse2Array(str);
output();
}
}
//用于输入的函数
void input(char* str)
{
int i = 0,j = 0;
char c;
str[0] = '/0';
printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++/n");
printf("请输入要解析的语句(esc退出):/n/n");
for(i=0;(c=getch())!='@';i++)
{
if(c==27)
exit(0);
if(c==8)
{
i-=2;
if(i<-1)
i=-1;
system("cls");
printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++/n");
printf("请输入要解析的语句(esc退出):/n/n");
for(j=0;j<=i;j++)
{
printf("%c",str[j]);
}
continue;
}
else if(c==13)
{
str[i] = '/n';
printf("/n");
}
else
{
str[i] = c;
printf("%c",c);
}
str[i+1] = '/0';
}
}
//将输入的字符串解析成一个一个的单词
void parse2Array(char* str)
{
int count;
int i,temp;
wordNum = 0;
count = strlen(str);
for(i=0;i<count;i++)
{
temp = i;
if(isOperator(str[i]))
{//如果是运算符
array[wordNum][0]=str[i];
array[wordNum][1]='/0';
wordNum++;
}
else if(isSeparator(str[i]))
{//如果是分隔符
array[wordNum][0]=str[i];
array[wordNum][1]='/0';
wordNum++;
}
else if(isChar(str[i]))
{//如果是字符
for(;str[i]!='/0'&&(!isOperator(str[i]))&&(!isSeparator(str[i]))&&(isChar(str[i])||isNum(str[i])||str[i]=='_');i++)
{
array[wordNum][i-temp]=str[i];
}
array[wordNum][i-temp]='/0';
wordNum++;
i--;
}
else if(isNum(str[i]))
{//如果是数字
for(;str[i]!='/0'&&(!isOperator(str[i]))&&(!isSeparator(str[i]))&&(isNum(str[i]));i++)
{
array[wordNum][i-temp]=str[i];
}
array[wordNum][i-temp]='/0';
wordNum++;
i--;
}
else
{
array[wordNum][0]=str[i];
array[wordNum][1]='/0';
wordNum++;
}
}
}
//输出信息
void output()
{
int i ;
printf("/n");
for(i = 0;i<wordNum;i++)
{
int flag = judge(array[i]);
switch(flag)
{
case 1:
printf(" 1、基本保留字:/t%s/n",array[i]);
break;
case 2:
printf(" 2、标识符 :/t%s/n",array[i]);
break;
case 3:
printf(" 3、常数 :/t%s/n",array[i]);
break;
case 4:
printf(" 4、运算符 :/t%s/n",array[i]);
break;
case 5:
if(strcmp(array[i],"/n")==0)
{
printf(" 5、分隔符 :/t//n/n",array[i]);
}
else if(strcmp(array[i]," ")==0)
{
printf(" 5、分隔符 :/t空格/n",array[i]);
}
else
{
printf(" 5、分隔符 :/t%s/n",array[i]);
}
break;
case -1:
printf("-1、不能识别 :/t%s/n",array[i]);
break;
default:
printf("-1、不能识别 :/t%s/n",array[i]);
break;
}
}
}
//判断是哪类字符(1、基本保留字 2、标识符 3、常数 4、运算符 5、分隔符 -1、不能识别)
int judge(char * word)
{
if(isSeparator_str(word))
{
return 5;
}
else if(isReservedWord_str(word))
{
return 1;
}
else if(isOperator_str(word))
{
return 4;
}
else if(isNum_str(word))
{
return 3;
}
else if(isIndentifier_str(word))
{
return 2;
}
else
{
return -1;
}
}
//判断是否是字符
int isChar(char c)
{
if(c>='A'&&c<='Z'||c>='a'&&c<='z')
{
return 1;
}
else
{
return 0;
}
}
//判断是否是数字(单个字符)
int isNum(char c)
{
if(c>='0'&&c<='9')
{
return 1;
}
else
{
return 0;
}
}
//判断是否是操作符(单个字符)
int isOperator(char c)
{
int i ;
char sign[] = {'+','-','*','/','%'};
for(i = 0;i<NUM_OPERATOR;i++)
{
if(c==sign[i])
{
return 1;
}
}
return 0;
}
//判断是否是分隔符(单个字符)
int isSeparator(char c)
{
int i ;
char sign[] = {'/n',' ','/"','/t',',',';',':','/'','<','>','(',')','{','}','[',']'};
for(i = 0;i<NUM_SEPARATOR;i++)
{
if(c==sign[i])
{
return 1;
}
}
return 0;
}
//判断是否是基本保留字(参数：字符串)
int isReservedWord_str(char* str)
{
int i ;
for(i = 0;i<NUM_RESERVED_WORD;i++)
{
if(strcmp(str,sign_reserved_word[i])==0)
{
return 1;
}
}
return 0;
}
//判断是否是操作符(参数：字符串)
int isOperator_str(char* str)
{
int i ;
for(i = 0;i<NUM_OPERATOR;i++)
{
if(strcmp(str,sign_operator[i])==0)
{
return 1;
}
}
return 0;
}
//判断是否是分隔符(参数：字符串)
int isSeparator_str(char* str)
{
int i ;
for(i = 0;i<NUM_SEPARATOR;i++)
{
if(strcmp(str,sign_separator[i])==0)
{
return 1;
}
}
return 0;
}
//判断是否是数字串(参数：字符串)
int isNum_str(char* str)
{
int i , count;
count = strlen(str);
for(i = 0;i<count;i++)
{
if(str[i]<'0'||str[i]>'9')
{
return 0;
}
}
return 1;
}
//判断是否是标识符(参数：字符串)
int isIndentifier_str(char* str)
{
int i , count;
count = strlen(str);
for(i = 0;i<count;i++)
{
if(!isChar(str[i])&&!isNum(str[i])&&(str[i]!='_'))
{
return 0;
}
}
return 1;
}
作者：wangchangshuai0010
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